The most amazing transformation started one year ago after Sergio Santos exhausted his three minor league options and was in danger of being a complete first-round bust as an infielder.

Santos had two assets left—a 98 mph fastball and the willingness to learn.

Thanks to those two traits, Santos, 26, emerged as the best story of the Cactus League and perhaps all of the exhibition season. Santos made the remarkable conversion from the infield to a major league pitcher in a span of one season with the White Sox.

The emotions took over as Santos called family members and supporters shortly after general manager Ken Williams informed him that he made the Opening Day roster.

"I'm thanking my lucky stars every day," said Santos, mindful that he achieved his goal of reaching the majors while quickly surpassing several former teammates who labored during his eight seasons in the minors. "I had my mom praying, just in case for backup. It's nice that when you work so hard for something to kind of be rewarded at the end of the day.

"I know there are so many people deserving of that same thing, but it just doesn't happen. So, I'm definitely thankful and very appreciative that I've been given the opportunity."

Manager Ozzie Guillen insisted that Santos earned the promotion despite pitching just 26 games in the minors and posting a 6.14 ERA for the Peoria Javelinas of the Arizona Fall League in 2009.

"The reason we kept you is because we know you can help us win games," Guillen told Santos. "This is not the instructional league. This is not a development situation. Our job is to try to win this division, try to win everything. Don't feel like we kept you because we didn't have any choice. I think you earned it."

It took some persuading by Sox farm director Buddy Bell for Santos to finally give pitching a try in the spring of 2009. Although Santos was a Diamondbacks first-round pick in 2002, he couldn't break into the rotation at Mater Dei High in Santa Ana, Calif. "We had three pitchers receive Division I scholarships," Monarchs coach Burt Call remembered. "But I'm not surprised by Sergio's determination."

Santos' eagerness never wavered as he pitched at four minor league levels. Despite a combined 8.16 ERA, Santos earned an invitation to the AFL on the basis of his fastball that enabled him to strike out 30 in 28 2/3 innings.

Several scouts—including some who watched him in high school—said that Santos would have been selected in the Rule 5 draft had the Sox not placed him on the 40-man roster because of his fastball. Only Stephen Strasburg threw harder among AFL prospects, according to Pitch F/X data. But Santos started to emerge in his first exhibition game at Tempe when he struck out the Angels' Peter Bourjos, Maicer Izturis and Freddy Sandoval with a changeup to complement his fastball.

Santos was unscored upon in his first six spring outings before showing some vulnerability with some wildness and rushing his tempo at the first sign of trouble. Pitching coach Don Cooper has emphasized some nuances with a runner on base, such as employing the slide step and pausing longer in the stretch position.

But after learning a new position and reaching the majors in one year, Santos is eager to improve.

"The sky is definitely the limit," Santos said. "I will try to be the best I can. I set really high goals for myself. Some are unattainable, but I try to go for them. You can never stop getting better at this game. That's what makes the best at their sport the best. They keep trying to get better and improve."